1. Field of the Invention
This invention is concerned with apparatus for separating different constituents of a sample of granular products, and more particularly with apparatus for separating various types of impurities mixed with grain, as well as separating broken and undersized grain from whole grain.
2. Description of the Prior Art
A grain abrading and cleaning apparatus is described in U.S. Pat. No. 2,696,861, wherein dust, flakes, and other impurities are removed from grain. U.S. Pat. No. 4,312,750 is a grain-cleaning apparatus which is mobile in nature and is based upon an inclined rotating screen drum. By means of rotating screen drums, foreign material is separated from grain. U.S. Pat. No. 4,840,727 describes a grain cleaner and an aspirator, wherein banks of decks are gyrating in a flat, horizontal plane, to move a sample of grain contaminated with impurities. An inspirator is used to move and separate the particles in a grain sample. In the foregoing patents, there is no provision for separating broken and undersized grain from whole kernels. In French Patent No. 8902764 there is described an automatic laboratory grain cleaner known as "the NSA system", wherein a whole sample is introduced into a weighing hopper and then routed by a vibrating distributor to a double-perforation cylindrical screen where dust and broken or undersized grain are extracted through a first perforated zone and then the good grain and middle-sized foreign material is extracted through a second perforated zone. Big-sized foreign materials are collected at the exit of the perforated zones. Blowers are used in conjunction with the cylindrical screen to assist in the separation of the foreign particles from the grain.
The devices described in the U.S. Patents also do not have any facilities for separating the components of a mixture and then identifying or classifying the separated components. On the other hand, the NSA system described in the French Patent separates the grain and the impurity particles to provide a percentage of foreign material, broken grain, and total defects, but is not accurate because of possible variation in the blower speeds and rotating screen speed.